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Gardening in Washington State

Archive for June 2015

Do plants get chicken pox? Help!!

Have you ever wondered what causes the spots on your salal bushes?

PCD1
Photo by  Linda Chalker-Scott

Landscape Plant Problems: A Pictorial Diagnostic Manual will help you identify all kinds of plant problems so that you can take steps to eliminate them. Vivid photos from real-life Northwest landscapes illustrate signs and symptoms of disease, insects and mites, and cultural or environmental problems as they occur on 78 popular ornamental and fruit-bearing plants. A special section shows problems common to a larger number of plants and signs of herbicide damage. The introduction provides five simple steps to identify and diagnose the cause of plant problems. Learn to use the clues WSU experts teach Master Gardeners.

You can order this spiral-bound manual (MISC0194) from WSU Publications. It sells for $35 plus tax and shipping. You may also be able to buy it at your County Extension office

Submitted by: Carrie R. Foss and Jenny Glass, June 22, 2015

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Beneficial Predators of Aphids Found in Fruit Trees

For nearly every plant in the home landscape, there is an aphid species that feeds on it. Fruit trees are no exception. Apples host a green apple aphid, cherries host a black cherry aphid (Myzus cerasi), and peaches and nectarines host a green peach aphid (M. persicae). While aphids rarely damage the fruit itself, they can compromise the health of a fruit tree, reduce the size of the fruit, and deposit a sticky substance called honeydew on the surface of fruit and leaves.

Green peach aphid
Green peach aphid. Photo by Mike Bush

There are many beneficial insects that graze on aphids, and in most years, these natural enemies do a fair job of keeping aphid populations in check. Beneficial insects include lady beetles, lacewings, syrphid flies, and parasitic wasps that sting and lay eggs in aphids. Learn to recognize these beneficial insects and conserve them. Many types of beneficial insects can be drawn to the home landscape by planting certain flowers in the yard, such as asters and legumes, as ground cover beneath the fruit tree. Perhaps one of the best ways to conserve these biological agents is to minimize pesticide use. Organic pesticides products should only be used when necessary to protect the fruit and maintain the health of your tree.

Lady beetle larva
Lady beetle larva. Photo by Mike Bush

For more information on organic management of tree fruit pests see the WSU Extension manual EM066E- Organic Pest and Disease Management in Home Fruit Trees and Berry Bushes by Drs. Charles Brun and Michael Bush on-line.

For more information on beneficial arthropods in the home landscape, see the WSU Extension manual EM067E- Beneficial Insects, Spiders, and Other Mini-Creatures in Your Garden: Who They Are and How to Get Them to Stay by Dr. David James on-line.

Submitted by: Michael R. Bush, June 8, 2015

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Blossom-end Rot of Tomato and Pepper

Blossom-end rot is a plant disorder that appears as a water-soaked, light brown spot on the blossom end of the fruit. As the fruit matures, the spot becomes sunken, leathery, and brown to black. Opportunistic pathogens can infect this spot leading to fruit rot. Blossom-end rot is associated with a lack of sufficient calcium in developing fruit. Often the disorder is only noticeable on the earliest maturing fruit of the season. Blossom-end rot may be traced to excessive soil moisture, drought stress, or excessive fertilization. Prior to planting next year’s crop, send a soil sample in for testing. Your county extension agent can recommend soil-testing laboratories in your area. If your soil is low in calcium, use lime or dolomite lime at least 2–4 months before planting. Plant in well-drained soils and water consistently. Mulching plants may be helpful. Fertilize moderately to avoid buildup of salts in the soil and to prevent excessive growth.

Blossom end rot on tomato Blossom end rot on pepper
Blossom end rot of tomato (left) and pepper (right)

Crops affected: Tomato, pepper, eggplant, and various cucurbits.

For more information on tomato blossom-end rot, see Growing Tomatoes in Home Gardens FS145E as well as WSU Hortsense

Submitted by: Michael Bush, June 8, 2015

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Garden Tip: WSU Master Gardeners can help you solve plant problems

You gaze out at your garden and notice your rose has yellow leaves.  Suddenly you realize your plant has a problem and you don’t know what to do to fix it.  It’s time to turn to your WSU Master Gardener Volunteer diagnostic clinic for help.

Rose virus

Where do you find your local Master Gardener diagnostic clinic?

Each WSU county with an active Master Gardening community has volunteers that provide diagnostic help.  See http://mastergardener.wsu.edu/program/county/ for your local program.

What type of your sample should you bring?

The plant problem sample you collect to bring to a diagnostic clinic should represent the types of damage you are seeing on the plant.  Since the WSU Master Gardener volunteer will likely not be able to visit the site, you may want to take some pictures to demonstrate the distribution of the problem on the plant and how the plant is situated in the garden or landscape.

What information should you provide?

Come prepared to answer questions.  You will be asked questions about the history and care of the plant as well as the onset of the problem.  The Master Gardener volunteers may also quiz you about environmental conditions and the landscaping practices used.

Source: Excerpted from WSU Plant Problem Diagnosis web page at http://puyallup.wsu.edu/plantclinic/samples/ppd.html .

Submitted by: Jenny Glass, June 2, 2015

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